Refs #4904. Checking if page has segments before using them.

1 files changed, 6 insertions, 2 deletions

diff --git a/mod/blog/lib/blog.php b/mod/blog/lib/blog.php
index 1ccfe4dc4..4dcc7d56e 100644
--- a/mod/blog/lib/blog.php
+++ b/mod/blog/lib/blog.php
@@ -411,8 +411,8 @@ function blog_url_forwarder($page) {
 	global $CONFIG;
 
 	// group usernames
-	if (substr_count("$page[0]/$page[1]", 'group:')) {
-		preg_match('/group\:([0-9]+)/i', "$page[0]/$page[1]", $matches);
+	if (substr_count(implode('/', $page), 'group:')) {
+		preg_match('/group\:([0-9]+)/i', implode('/', $page), $matches);
 		$guid = $matches[1];
 		$entity = get_entity($guid);
 		if ($entity) {
@@ -426,6 +426,10 @@ function blog_url_forwarder($page) {
 		}
 	}
 
+	if (!isset($page[0])) {
+		return;
+	}
+
 	// user usernames
 	$user = get_user_by_username($page[0]);
 	if (!$user) {